Ta Jerry. I have pulled it out and it was actually pretty full of crap. There was also some spongy strips blocking it up too. I won`t know for sure yet if this is the cause until I try running water over the car again but I`m pretty confident it is.

BUT, I thought u said it was easy to get back on? Its a real bit*h! I have had to leave it overnight now as I cant get it back on again. A part of the upper heat shield (I think thats what it is called) was tight up against it and now the tube thing is off I cant get it back on. I`ll have another go tomorrow but might end up having to loosen the heatshield a bit.

Under the vents at the outside base of the windshield, there's a well. This well drains via a rubber tube that comes out of the firewall into the engine compartment. This tube is flat with a wide slit-like opening, and it therefore clogs easily with the debris that falls down into the well. When this happens, the water can't drain and eventually makes its way to your floorboard. When you open the hood, the rubber tube is on the firewall on the passenger side, right behind the engine block. It pulls off and goes back on pretty easily. Just ram a coat hanger or something through it to clean it out. I bet this will fix your problem.